Vapor and gas power plant utilizing equipressure vapor generator



Oct. 14, 1952 E. MERCIER ET AL VAPOR AND GAS POWER PLANT UTILIZING EQUIPRESSURE VAPOR GENERATOR Filed Dec. 29, 1945 V/ E 50 m ma 6 7 TIM; T Nl mmu m Md ff 5 M Patented Oct. 14, 1952 I I VAPOR AND GAS POWER PLANT UTILIZING EQUIPRESSURE VAPOR GENERATOR Ernest Mercier. and Marcel, Ehlinger, Paris, France, assignors, by mesne assignments, to Moore, Inc.,.AI :lanta, Ga., a corporation of Georgia Application December 29, 1945, Serial No. 638,054

. l France February 16, 1945 .16 Claims.

This invention consists in employinga boiler fed with combustion-sustaining air at a high. pressure in the order of 40 to 120 .kg per sq. centimeter, or even higher, generating steam at the same pressure, according to the application of Ernest Mercier Ser. No. 472,217, filed January 13, 1943, in the United States Patent Omce, now

abandoned, and simultaneously feeding a gas turbine and a steam turbine preferably mounted on the same shaft, thecompressed air bein supplied by free piston engine compressor units. The application of Ernest Mercier, Serial No. 103,893, filed July 9, 1949,. now Patent No. 2,547,135, issued April 3,. 1951,. which is a continuation in part of the application Serial No. 472,217a1so discloses a plant utilizing a boiler generating steam at equipressure or approximating the pressure of the gas in the combustion chamber. In the application and in the patent means are disclosed forcontrolling the fuel and compressed air supply to the combustion cham- I her so as to maintain the relation of the gas pressure to the steam pressure. 1 v

The driving elements of these .free piston engine compressor units can be either two-cycle or four-cycle internal combustion engines fed with liquid, gaseous or colloidal-fuel, or engines fed with compressed air or gas, or steam engines.

A highly valuable case in relation to; this in-' vention is the one where internal combustion engines of whatever type are utilized to drive the compressors, such a combination being consistent with quite a series of highly profitable recoveries the apparatus for which will be defined in thefollowing.

The figure of the appended drawing gives the general diagram of the arrangement.

I3, I, 2 and 3 are free piston heat-engines which,

drive compressors 0', I, 2 and 3 respectively.

I! is a scavenging compressor which suppliesthe air necessary for the operation of engines I], I, 2 and 3. Preferably, said engines are supercharged, the supercharging pressure and conse quently the delivery pressure of :compressor 0' being preferably in the order of 3 to 4 kg. per sq.

centimeter. Compressors I,-.2 and 3 work in three stages which correspond to the low pressure, the medium pressure and the high pressure stages respectively. The common "compression.

ratio in each stage may be substantially in the.

range between aboutz3.5 to" 1 and; to 1. The

obtaining maximum 'efii'ciencywiii the gas cycle, 1

that is, when the combustion chamber pressure is pressures in the range between 45 and kg. per sq. centimeter.

While undergoing compression the air is cooled between compressors I' and 2 in a cooler 4 and between compressors 2 and 3' in a cooler 5 by the condensate as hereinafter described. If possible and where the power of the plant makes it worth while, it is also profitable to cool. the cylinders of compressors I', 2' and 3 for ex-' ample, by means of jackets confining a cooling fluid, in order to approximate isothermal compression conditions to a certain degree.

Now, an essential feature of the cycle is that thecompressed airafter leaving the high-pressure compressor 3 is directed through a heatexchanger' 6 in which-it is re-heated by the exhaust gases from the heat-engines I3, I, 2 and 3. The airleaves this heat-exchanger at a temperature of, say, 550 C.; the gases, for their part, are cooled down to a temperature of, say, 230 C. r 7

Another essential feature of the cycle is that the gases thus cooled down are directed into that stage of the gas turbine 8 which corresponds to their pressure, due regard being had to head losses undergone thereby and which, of course,

should be minimizedas far as possible.

For its part, as already stated,,the re-heated high pressure. compressed air is admitted into the combustion chamber 7 of a boiler having steam generating elements Ia. Means may be provided in accordance with the application Serial No. 472,217 above mentioned for maintaining equality between thev steam and gas pressures. The burners I3 of the boiler may be operated to burn that amount of fuel which is nec.

essary to bring the air and combustion gas temperature to the maximum value permitted by the gas turbine, say, 600 (3., as limited by available materials or other factors.

The air thus re-heated and the combustion gases are admitted into the gas turbine 8. ,j-

In-its principle the gas cycle could'belimited to' that developed in. the aforesaid apparatus elements, namely, the engine compressor units the heat exchanger fi'to heat the compressed air and then being delivered to a reduced pressure stage of the gas turbine for further expansion therein together with gases from the combustion chamber, and this is one of the cycles expressedly aimed at by this invention. The gas turbine is connected to the combustion chamber so that the intake'pressure of the gas would be, as already stated, in the order of 45 to 65 kg. per sq. centimeter. Of course, the actual point of highest efliciency of this gas cycle depends, on the one hand, on the efiiciency attained by the air compressing means, on the other hand on the gas turbine efliciency, and finally on the efficiency of the cooling and heat-exchanging processes by which heat otherwise lost is recovered in the gas. At any rate, the gas cycle thus conceived is far better than the usual cycle of the conventional free piston power generators. that is, prime movers operating air compressors. as far both as the ultimate thermodynamic efiiciency and the effective power available on the gas turbine shaft per kilogram of fuel burnt in the free piston heat engines are concerned. This is due particularly to the considerably higher intake pressures and temperatures of the gas turbine resulting from effecting combustion at a pressure of the degree of the steam pressure.

However, the gas cycle above described may be supplemented with substantial advantage as follows:

If an additional amount of fuel be burnt in the boiler combustion chamber 1' over and above that merely to supply the heat in the gas as required in the gas cycle as above described, preferably the oxygen in the compressed air supplied being substantially completely consumed, the boiler is capable of generating in the steam generating elements Ia from the heat released, in addition to the gases at 600 C. and at a definite pressure, steam which also may be at substantially the same pressure and which can also be at a temperature of 600 0., since that type of boiler easily admits of higher superheating temperatures than do conventional boilers.

It is to be observed that the steam cycle in which the steam is generated substantially at the same pressure as the combustion gases, because of the high pressure of the .gases in the combustion chamber containing the steam generating elements, is far more valuable from the point of view of the overall efiiciency of the plant than the normal cycle of a steam turbine and a boiler running at the same initial steam temperature and the same initial steam pressure, the boiler being fed with air at normal pressure.

The advantage derives from the fact that, in the case of the present invention providing a gas and steam generating and utilizing plant as defined above, the efficiency can be calculated legitimately as if the loss at the boiler chimney were nil and, on the other hand, as if the power consumed by the air supplying and fuel feeding devices were also nil. This is due to'the fact that the corresponding expenses instead of being charged only against the steam producing part of the plant, may be entered on the .debit side in the account of the gas cycle as defined above which undergoes no appreciable modification by the addition of steam generating elements in the combustion chamber, steam being produced by the so-called equipressure" boiler, as above indicated, merely by the burning of additional fuel and without loss of heat to the stack. More exactly, the gas cycle is improved slightly on account of the gases produced under pressure containing a considerably higher percentage of CO2.

4 such alteration being to the advantage of the ultimate efficiency.

Thus, the aforesaid combination, although residing in the association with a highly efficient gas cycle of a steam cycle having a substantially lower efliciency, possesses a most considerable economical value.- The advantage may be secured where a solid fuel (powdered coal) or a gaseous fuel (blast-furnace gas, natural gas) is burnt in the boiler as well as with liquid fuels.

The'inventionv also includes the specific case where mercury instead of water is vaporized in the boiler. In that instance, with a mercury vapour temperature limited to 600 C., the boiler pressure must be brought down to 22 kg. per sq. centimeter. This involves a slight lowering in the gas cycle efiiciency, because of reducing the gas pressure also to 22 kg. per sq. centimeter to maintain equipressure, but also a very appreciable improvement in the. efliciency of the vapour cycle, whereby such a combination becomes a very profitable one.

In the combined gas and steam generating and utilizingplant the provision of the steam turbine 9 and its condenser 90. will make additional thermal unit recovery possible by which the ultimate efficiency can be further increased materially. Such recovery is effected as follows:

A portion of the water condensed in the steam turbine condenser 9a is sent as usual to one or more bleeder heaters such as in and thence to boiler 1. An additional portion is availed of as'follows. This additional portion of the condensate is sent first to a cooler II in which it is brought down close tothe temperature of the cooling water flowing through the cooler II. This cooled condensate is availed of in the two coolers 4 and 5 above described for cooling the air between stages in the course of its compression, the coolers 4 and 5 being fed in parallel. These'coolers, into which the compressed air is admitted at a temperature of, say, 140 C., are so designed that the whole of the cooling condensed water will leave these coolers at a temperature of about C. and a pressure of, say, 3.5 kg. per sq.'centimeter. This portion of the water is then forced into the cooling jackets of combustion engines 0, I, 2, 3 in which it is converted entirely into steam at a temperature of 138 C. and a pressure of 3.5 kg. per sq. centimeter. I

This steam thence is sent into the stage of the steam turbine 9 which is at the corresponding pressure for the recovery therein of the corresponding mechanical power by expansion of this steam in this turbine together with the steam generated in the steam generator.

The conditions of recovering the heat otherwise lost by coolin of the internal combustion engines according to this invention are made possible by reason of the perfect stability of the steam turbine in which the recovered steam is a supplement to the steam generated in the boiler. Of course, an even increased stability is obtained where both the steam and the gas-turbines are keyed to one and the same shaft as diagrammatically indicated in the drawing.

Finally, as far aspressure equilizing is concerned, this invention provides the following simple and eflicient method. The power regulator of the turbine pair, controlled e. g. by an ordinary tachometric mechanism, influences the admission into one turbine only in the pair, e. g. to the steam turbine. As to the admission into the second turbine; (the gas. turbine in this example),

wear

,just in the reverse way upon the steam feed,

which provides for great responsiveness inthe control.

In the drawing the spaces below and above the piston of differential device respectively are connected to the gas and steam delivery pipes.

The piston is connected through a bell crank lever and a rod to the valve 22 in the pipe carrying the gas to the gas turbine 8 so as to close and open this valve upon decrease and increase of the gas pressure relative to the steam pressure. Thepower regulator or governor Valve 24 controls the steam delivered to the steam turbine 9 in response to variations in the power load jointly carried by the two turbines 8 and 9. If the gas pressure falls relative to the steam pressure and the valve 22 thereby is throttled as above mentioned, thus reducing the power developed in thegas turbine 8, the governor valve 24 opens to increase the delivery of the steam to the steam turbine 9 to develop increased power therein. Increase of the gas pressure relative to the steam pressure will produce the reverse action of valves 22 and 24 and opposite shifting of the load between the two turbines.

This invention especially covers the case where the internal combustion engines are fed with a gaseous fuel or with colloidal coal, that is, with a liquid fuel admixed with powdered coal.

What we claim as our invention and desire to secure by Letters Patent is: f

1. Power generating plant comprising means providing a combustion chamber for combustion of fuel therein, means for effecting combustion of fuel in said combustion chamber to produce gases at a pressure substantially above atmospheric pressure, a main prime mover connected to said combustion chamber for utilizing the gases therefrom under said pressure, to develop power in said main prime mover by expansion of said combustion gases, means for compressing a combustion supporting gas to a pressure effective for delivering said gas to said combustion chamber against the pressure of the combustion gases therein, said combustionv chamber being connected to said compressing means to receive said compressed gas therefrom, an auxil-.

iary prime mover, means cooperating with said auxiliary prime mover for effecting utilization therein of gases at high temperature and at a pressure to develop power therefrom by expansion thereof in said auxiliary prime mover to an exhaust pressure substantially correspondingi'to the pressure of said expanding combustion gases in a reduced pressure stage of said main prime mover, said auxiliary prime mover being operatively connected "to said compressing means for driving said compressing means independently of said main prime mover to effect said compression of said combustion supporting gas, and means fordelivering the exhaust gases from said auxiliary prime mover driving said gas com pressing means to said reduced pressure" stage of said main combustion gas utilizing prime t e comitantlywith further expansion of said combustion gases in said main prime mover from said reduced pressure.

. 2 Power, generating plant "comprising meansproviding a combustion chamber for combustion of fuel therein, means for effecting combustion of fuel in said chamber to produce gases at a pressure substantially above atmospheric pressure, a main primemover connected'to said combustion chamber for utilizing the gases therefrom under said pressure to'develop power in said main prime moverby expansion of said. combustion gases,

means for compressing a combustion supporting gas t oa. pressure effective for delivering ,said gas to said combustion chamber against the pressure, of the combustion' gases ftherein,v an auxiliary prime mover, means cooperating with said auxiliary prime mover for effecting utilization therein of gases at high'temperature and at a pressure to develop power therefrom by expansion thereof in said auxiliary prime mover to an exhaust pressure substantially corresponding to the pressure of said expanding combustion gases in a reduced pressure stage ofsaid main prime mover, said auxiliary prime mover being operatively connected to said compressing means for driving said compressing means independently of,

said main prime mover to effect said compression of said combustion supporting gas, a heat exchanger connected to said gas compressing means to receive said compressed combustion supporting gas therefrom andconnected to' said auxiliary prime mover to receive said exhaust gases therefrom heating said compressed gas by the heat of said exhaust gases substantially at said reduced pressure, said combusti'onchamber being connected to said heat exchanger toreceive said heated, compressed combustion supporting gas therefrom, and means for delivering said auxiliary prime mover exhaust gases from said heat ex-v changer to said reducedpressure stage of said main combustion gas utilizingprime mover for further expansion of said; exhaust gases in said main prime mover concomitantly with further expansion of said combustion gases from said reduced pressure to develop power therefrom. I

3. ,Powergenerating plant comprising means providing a combustion chamber for combustion of fuel therein, means for effecting combustion haust gases by further expansion thereof conof fuelin said combustion chamber to produce combustion gases at a pressure substantially above atmospheric pressure, a main gas utilizing prime mover connected to said combustion chamber for utilizingthe gases therefrom under said pressure to developpower. in said main prime mover by expansion of said combustion gases, a steam generator within said combustion chamber and heat-- ed by said combustion gases for generating steam at a pressure elevated substantially above atmospheric pressure, a steam utilizing prime mover connected to. said steam generator to receive the generated steam therefrom and for utilizing said steam by expansion thereof to generate power therefrom, means for compressing a combustion supporting gas to a pressure effective to deliver said gas to said combustionchamber against the pressure of the combustion gases therein, said combustion chamber being connected to said compressing means to receive said compressed combustionsupporting gas therefrom, an auxiliary prime mover, means cooperating with said auxiliary prime mover for effecting utilization therein' of gases athigh temperature and at a pres thereofin said auxiliary prime mover to an ex- 7 haust pressure substantially corresponding to the pressure of said expanding combustion gases in a reduced pressure stage of said main gas utilizing prime mover, said auxiliary prime mover being operatively connected to said compressing means for driving said compressing means independently of said main gas utilizing prime mover to effect said compression of said combustion supporting 'gas, means for passing water in heat exchanging relation to said auxiliary prime mover to abstract heat from said gases initially at high temperature as they are utilized for developing said power for said compression and to generate steam therefrom at a pressure substantially corresponding to a'reduced pressure stageof said ste'amutilizing prime mover, means for delivering said steam generated by said abstracted-heat to said reduced pressure stage of said steam utilizing prime mover for further expansion therein concomitantly with expansion from said reduced pressure of the steam generated'in said steam generator, and means for delivering the exhaust gases from said auxiliary "prime mover driving said compressing means to said reduced pressure stage of said main combustion gas utilizing prime mover to develop therein power from said exhaust gases by further expansion thereof concomitantly with further expansion of said combustion gases in said main prime mover from said reduced pressure.

4. Power generating plant as defined in claim 3 which comprises means for condensing the steam discharged from said'steam utilizingprime mover, said means for passing water in heat exchanging relation to said auxiliary prime mover to generate steam therefrom beingconnected to said condensing means to receive the condensate therefrom for passage in said heatexchanging relation for generating the steam therefrom for delivery to said reduced pressure stage of said steam utilizing prime mover.

5. Power generating plant as defined in claim 4 which comprises a heat exchanger connected to said condensing means and to said compressing means 'f'or receiving said condensate and said combustion supporting gas and heating said con-- densate by the heat of said gas developed in the compression thereof before delivery of said condensate to said means for abstracting heat from said auxiliary prime mover. I

6. Power generating plant comprising a combustion chamber for combustion of fuel therein,-

means for efiecting combustion of fuel in said chamber to produce combustion gases at a pressure substantially'above' atmospheric pressure, a maingas utilizing prime mover connected to said combustion chamber for utilizing the gases therefrom under said pressure to develop power in said main prime mover by expansion of said combustion gases, a steam generator withinsaid combustion chamber and heated by said combustion gases for generating steam at a pressure adapted for development of power therefrom, said combustion gas pressure in said chamber approximating that of the steam, a steam utilizing prime mover connected to said steam generator to receive the generated steam therefrom for utilizing said steam by expansion thereof to generate power therefrom, means for compressing a combustion supporting gas to a pres-'- sure effective to deliver said gas to said combustion'chamber against the pressure ofthe combustion gas therein, an auxiliary prime mover, means-cooperating 'with said auxiliary prime mover for' efiecting utilization therein orgasesat acrea e high temperature and at a pressure to develop powertherefrom-by expansion thereof in said auxiliary prime mover to an exhaust pressure substantially corresponding to the pressure of said expanding combustion gases in a reduced pressure stage of said main gas utilizing prime mover, said auxiliary prime mover being operatively connected to said compressing means for driving said compressing means independently of said main gas utilizing prime mover to effect said compression o'f'said combustion supporting gas, a heat exchanger connected to said gas compressing means to receive said compressed combustion supporting gas therefrom and connected to said auxiliary prime mover to receive said exhaust gases therefrom for heating said compressed gas by the heat of said exhaust gases substantially at said reduced pressure, said combustion chamber being connected to said heat exchanger to receive said heated compressed combustion supporting gas therefrom, means for delivering said auxiliary prime mover exhaust gas from said heat exchanger to said reduced pressure stage of said main combustion gas utilizing prime mover for furtherexpansion of said exhaust gases in said main prime mover in cooperation with said combustion gases to develop power therefrom, means for passing water in heat exchanging relation to said auxiliary prime mover to abstract heat from said gases initially at high temperature as said gases are utilized therein for developing said power for said com pression to generate steam from said water at a pressure corresponding to a reduced pressure stage of said steam utilizing prime mover,-and means for delivering said steam generated by said abstracted'heat to said reduced pressure stage of said steam utilizing prime mover for further expansion thereinfrom said reduced pressure in cooperation with the steam generated in said steam generator.

'7. Power generating plant comprising means providing a combustion chamber for combustion of fuel therein, and means for effecting combustion of fuel in said combustion chamber to produce combustion gases at a pressure substan-' tially above atmospheric pressure, a gas turbine connected to said combustion chamber for utilizing the gases therefrom under said pressure to develop power in said turbine by expansion of said '-combustion gases in a plurality of stages; a steam generator within said combustion chamber heated by-said combustion gases for generating steam at a pressure approximating that of the combustion gases in said chamber, a steam turbine connected to said steam generator to receive the generated steam therefrom and for utilizing said steam'by'expansion thereof in a plurality ofstages to-generate power therefrom, a free piston compressor for compressing air to a pressure effective to deliver said air to said combustion chamber against the pressure of the combustion gases and connected to said combustion chamber to deliver said compressed air thereto for supporting the combustion therein, a free piston internal combustion engine operatively'connected to said air compressor for driving said compressor to effect said compression of said air, said internal combustion engine being adapted to exhaust the gases therefrom at a pressure substantially corresponding to the pressure of a reduced pressure stage of said gas turhim and connectedto said reduced pressure stage to deliver said" exhaust gases thereto, said internal combustionenginebeing constructed with a water jacket for cooling thereof, means forpassing water throughsaid water jacket to'abstract heat fromsaid engine and to generate steam therefrom at a' pressure substantially-corresponding to "a reduced pressure 'stage of said steam turbine, said water jacket being {connected to said reducedpressure stage of said steam turbine for delivering thereto said steam generated by said'abstractedfheat for c'ooperationup'onfurther expansion "in said steam turbine-with the steam generated-in said'steam generator to develop power therefrom;

8. A power generating plant comprising a main prime mover utilizing a gas under pressure to develop power therefromby expansion of said gas, meansfor compressing a gas'to a pressure effective for developing power therefrom in said main prime mover, said main prime mover being connected to said compressing means to receive said compressed gas therefrom, an auxiliary prime mover, means cooperating with said auxilsure stage ofsaid main-gas utilizing prime mover I I to develop power therein" from said exhaust gases concomitantly with furtherexpansion of said compressed gas in said-main "prime mover from said reduced pressure. a

9. A power generating plant comprising a main prime mover utilizing a gas under pressure to develop power therefrom by expansion of said gas, means for compressing agas-to a pressure effective for developing power therefrom in said main prime mover, arijauxiliary prime mover, means cooperating witlifsaid auxiliary prime mover for effecting utilization therein of gases at high temperature and'at a pressure to ,develop powertherefrom'by expansion thereof in said auxiliary prime mover to an exhaust pressure substantially corresponding to the pressure of said expanding compressed gas in a reduced pressure stage of said main prime mover, said auxiliary prime mover-being operatively connected to said compressingmeansjfor drivingsaid compressing means independently of said main prime mover to effect said compression of said gas, aheat exchanger connected to said compressing means to receive said compressed gas' therefrom and connected to said auxiliary prime mover to receive said exhaust gases therefrom for heating said compressed gas by the heat of said exhaust gases substantially at said reduced pressure, said main prime mover being connected to said heat exchanger to receive said heated compressed gas therefrom for expansion in said main prime mover, and means for delivering said auxiliary prime mover exhaust gases from said heat exchanger to said reduced pressure stage of said main prime mover for further expansion of said exhaust gases in said main prime mover concomitantly with further expansion of said compressed gas from said reduced pressure to develop power therefrom,

10. A power generating plant comprising a main prime mover utilizing a gas under pressure to develop power therefrom by expansion of said gas, an internal combustion engine developing gases therein at high temperature and at a pressure for expansion therein to an exhaust pressure substantially corresponding to the presfrom in said main prime mover, said main prime mover being connected to said second compressor to receive said compressed power developing gas therefrom 'for developing power in said main prime mover by expansion of said compressed gastherein, said compressors being operatively connected to said internal combustion engine to be driven thereby independently of said main prime mover to effect compression of said gases insaid compressors, and means for .delivering exhaust gases from said internal combustion enginextosaid reduced pressure stage of said main prime mover to develop power therein from said exhaust gases concomitantly with further expansion of said compressed power developing 'gas in said main prime mover from said reduced pressure. i

11. A power generating plant as defined in claim 1 which comprises a vapor generatordisposed in relation to said combustion chamber so as to be heated by said combustion gasesiproduced therein for generating vapor at a, pressure elevated substantially. above atmospheric pressure, and a vapor utilizing prime mover connected to said vapor generator to receive the generated vapor therefrom and for utilizing said vapor by expansionthereof to generate power therefrom. a 1

12. A power generating plant as defined in claim 11 in whichsaid vapor generator is'disposed within said combustion chamber, said combustion chamber being adapted to confine said combustion gases at a pressure of the degree of the pressure of the vapor gene'rated'in said 'vap'or generator. a

13. A- power generating plant comprising a'turbine utilizing a gas under pressure to develop power therefrom by expansion of said gas there in, a' free piston compressor for compressing a gas to a pressure effective for developing power therefrom in said turbine, said turbinebeing con-- nected to said compressor to receive said corn pressed gas therefrom, a free piston prime mover. means cooperating with said free piston prime mover for eifecting utilization therein of gases at high temperature and at a pressure to develop power therefrom by expansion thereof in said free piston prime mover to an exhaust pressure substantially corresponding to the pressure of said expanding compressed gas in a reduced pressure stage of said turbine, said free piston prime mover being operatively connected to said free piston compressor for driving said compressor independently of said turbine to effect said compression of said gas, and means for. delivering the exhaust gases from said free piston prime mover to said reduced pressure stage of said turbine to develop power therein from said exhaust gases concomitantly with further expansion of of said combustion gases, developing power from said vapor by expansion thereof, controlling a selected one of said fluids to vary the power developed therefrom in response to variations in the combined power developed by said expansions of said fluids, and controlling another of said fluids to vary the power developed therefrom in response to variations from said predetermined relation of said pressures of said fluids.

15. The method of operating a power generating system utilizing two heat conveying fluids under pressure which comprises effecting combustion of fuel to produce combustion gases at a pressure elevated substantially above atmospheric pressure, delivering said gases to a gas utilizing prime mover and developing power therefrom in said prime mover, generating vapor by the heat of said combustion at a pressure of the degree of the pressure of said combustion gases, delivering said vapor to a vapor utilizing prime mover and developing power therefrom in said vapor utilizing prime mover, controlling the delivery of a selected one of said fluids to vary the power developed therefrom in response to variations in the combined power developed from said fluids in said prime movers, and controlling the delivery of the other of said fluids so as to decrease and increase the power developed from said other fluid respectively upon decrease andincrease in the pressure of said other fluid relative to the pressure of said selected fluid.

16. A power generating plant utilizing two heat conveying fluids under pressure comprising means providing a combustion chamber for combustion of fuel therein, means for effecting combustion of the fuel in said combustion chamber to produce gases at a pressure substantially above atmospheric pressure, a gas utilizing prime mover connected to said combustion chamber to receive therefrom the gases under said pressurefor utilizing said gases to develop power in said gas utilizing prime mover byexpansion of said combustion gases, a vapor generator heated by said combustion gases for generating vapor at a pressure which is substantially above atmospheric pressure in a predetermined relation to the pressure of said combustion gases, a vapor utilizing mover. 20

Number prime mover connected to said vapor generator to receive the generated vapor therefrom and for utilizing said vapor by expansion thereof to generate power'therefrom, said prime movers being connected together was jointly to develop the power delivered. by said-plant, means responsive to variations in the power load jointly carried by said prime movers for varying the delivery of the heat conveying fluid to a selected one of said prime movers directly in relation to such power load variations, and means responsive .to variations from. a predetermined difference between the pressures of said fluids for decreasing and increasing the delivery of the heat conveying fluid to theotherprime mover upon decrease and increase in the pressure of said fluid delivered to said other prime mover relative to the pressure of said fluid delivered to said selected prime ERNEST MERCIER. 1 MARCEL EHLINGER.

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Pressure-Fired Boilers," published in Power Plant Engineering, March 1933; pages 119 and 120i 

